NACA-ACR-3L08

Abstract

INTRODUCTION <br>The NACA has been conducting an extensive wind-tunnel investigation to determine the aerodynamic characteristics of various types of airplane control surface in order to supply data for design purposes. This investigation has been conducted primarily with two-dimensional-flow models in the LMAL 4- by 6-foot vertical tunnel. Existing equipment has recently been modified in order to test control surfaces of finite span in three-dimensional flow in the LMAL 7- by 10- foot tunnel. Several airplane tail surfaces have already been tested as finite-span models, and the control-surface investigation is still in progress, both two-and three-dimensional-slow tests being made. <br>Two-dimensional-flow pressure-distribution measurements have been made of an NACA 0009 airfoil with various sizes of plain flaps and tabs (references 1 to 3). These data have been analysed and parameters for determining the aerodynamic section characterized of a thin symmetrical airfoil with plain, sealed flaps of any chord have been experimentally established (reference 4). Certain theoretical relationships developed by Glauert and Perring (references 5 and 6) from lifting-line theory for a thin airfoil with multiple flaps are reviewed in reference 4.